Personality of plants

LIFE OF A PLANT
minerals soluble, and by a strange intelligence,
select the kind and amount of material they take
in. In certain groups of plants, notably the
Legumes, colonies of Bacteria take the place of
root hairs, and by a reciprocal action, provide
the plant with the nitrogenous elements which
it craves.
The principal food of most vital importance
taken in by the roots is nitrogen. Nitrogen is
one of the basic elements of protoplasm, the
life fluid of the living cell. Where there is
life, there is nitrogen. Sulphur, phosphorous,
silica, iron and other elements are also needed
in small quantities.
The root hairs are constructed so as to allow
fluids to pass in but not out. The continual ab-
sorption of water results in a mechanical pressure
which automatically forces the sap up
through the stem to all parts of the plant. The
process is aided by the evaporation of water
from the leaves, through the partial vacuum
created by them at the top of the system.
Pushed from below and pulled from above,
the sap of a tree, for instance, moves with a pro-
[3i]